Syria is taking another step towards international respectability with a visit by David Miliband, Britain's foreign secretary, which is designed, in part, to encourage the new US administration to follow suit.

Miliband is due in Damascus next week as part of a wider Middle East tour at a time that western diplomatic efforts are focused on how to keep the faltering regional peace process alive.

The Foreign Office said he would also be visiting Israel and the occupied Palestinian territories, but gave no further details.

Syria has been shunned by the Bush adminstration for years, and last month's US special forces raid across the Iraqi border against an alleged al-Qaida target triggered angry protests at Bush's "cowboy policies."

But Barack Obama has made clear that he will change tack and seek to talk to the Syrians, who are delighted at the prospect. Miliband, in the role of transatlantic bridge-builder, will be encouraging him to do so.

The foreign secretary is due to meet his Syrian counterpart, Walid al-Muallem, who was in London recently, but he is also likely to see President Bashar al-Assad, who wants to build on the momentum of recent months and emphasise his role as an indispensable player in the region.

Analysts argue that Syria is a key state. It has held several rounds of inconclusive, Turkish-brokered talks with Israel over the Golan Heights, despite an Israeli attack on an alleged nuclear reactor last year. It is a key sponsor of Hizbullah, the Lebanese Shia movement, and a supporter of Hamas, the Palestinian Islamists who control the Gaza Strip and oppose the western-backed Palestinian Authority. Most significantly it is the only Arab ally of Iran, which is locked in confrontation with the international community over its nuclear ambitions.

In recent months Assad has made strenuous efforts to improve Syria's image. Encouraged by the French president, Nicolas Sarkozy, he has placed its relations with neighbouring Lebanon on a more stable and equal footing by establishing diplomatic ties for the first time since both countries won their independence from France.

Syria also helped broker the deal ending the long impasse between rival factions in Lebanon, using the clout it retains despite having been forced to withdraw its forces in 2005, following the assassination of the former Lebanese prime minister, Rafiq al-Hariri.

A key question for any rapprochement with Syria is the progress of the UN special tribunal investigating the Hariri killing. Syria denies any involvement but the indictment of any of its officials would clearly be a grave embarrassment.

Diplomats believe that a thaw with Syria could also trigger peace talks between Israel and Lebanon too, especially if Israel can be persuaded to withdraw from the tiny enclave of the Shebaa farms, where the borders of all three countries meet. If that were to happen, it would weaken the claim of Hizbullah to be resisting Israeli occupation — and discomfit Iran.

Meanwhile, Moallem suggested Israeli bombs may be the source of uranium traces that diplomats at the UN's nuclear watchdog, the IAEA, claim were found at the suspected nuclear site bombed by Israel.

"No one has ever asked himself what kind of Israeli bombs had hit the site, and what did they contain?" said al-Moallem, adding that the US has used bombs containing depleted uranium in Iraq and Afghanistan. "These media leaks are a clear-cut signal that the purpose was to pressure Syria. This means that the subject is not technical but rather political."